Numerous technical applications aim to convert a translational motion, in particular an oscillating translational motion, into a rotational motion so as to use the rotational motion to produce electric current by means of a generator. For example, the piston in a reciprocating engine is set into translational motion by the combustion of fossil fuels and by guiding the piston in a cylinder, whereby the piston transfers its translational kinetic energy via a piston rod onto a crankshaft whose rotational motion can in turn drive a generator to produce electric current. However, the use of a crankshaft implies a constant stroke as can be guaranteed by combustion engines, for example. In combustion engines, the stroke of the piston is matched with the diameter of the trajectory of the crankpin. If the translational motion is irregular, i.e. with a varying stroke, this kind of motion transfer from translational to rotational cannot be applied.
Another way of converting translational motion into rotational motion is the so-called rack-and-gear principle, whereby a translationally moving rack sets a translationally static gear into rotational motion. In the case of a piston moving in an oscillating translational manner, the oscillating motion of the rack (piston rod) via gears and implemented by means of suitably mounted freewheel units can be converted into a unidirectional rotational motion which can in turn be used by a generator to produce electrical current. Even though this type of motion conversion of straight strokes into a rotational motion is capable of converting strokes of different sizes into rotational energy, the transmission required for this purpose is mechanically complex due to the need for the two freewheel units; what is more, it is sensitive in terms of environmental conditions such as weather and therefore relatively high-maintenance. As a result, this type of motion conversion is not suitable for ensuring trouble-free operation over an extended period of time.
If the aim is to convert the power of ocean waves into electric current, sensitive systems can only be used to a limited extent to convert oscillating wave motion into a rotational motion, since rough weather conditions have a highly corrosive impact on such systems, thereby influencing them negatively in their function and efficiency. Protection such as in the form of a sophisticated mechanical system consisting of freewheel units mounted in the opposite direction, for example, is very elaborate and high-maintenance. For this reason, generating electric current from ocean waves by means of such systems is liable to disruption and requires much servicing, so the approach is often uneconomical or even unfeasible.
Ocean waves always produce a slow, vertically oriented buoyancy force as a wave crest passes through. What is more, the wave height or amplitude, i.e. the vertical difference in level between the wave trough and crest, does not remain constant. This means that the lifting motion that a floating body undergoes on the surface of the water, e.g. in the sea, is variable and will depend on the weather conditions and other environmental factors such as tides, geographical circumstances, shipping, etc. A wave power plant as described in DE 10 2008 048 730 B1 shows numerous flat floating bodies, largely arranged side by side, powered by wave motion and independently movable back and forth on guide rods in an oscillating, translational manner, i.e. up and down. The floating bodies are connected in an elastically preloaded manner to a support structure via a guide rod so that when a wave passes, the floating bodies are initially raised upwards vertically along the guide rod, acting against a spring force. After the wave has passed, the spring then moves back down along the guide rod into a wave trough with the gravity of the floating bodies.
In order to use this translational motion to generate electric current, i.e. electrical energy, it is essentially possible to apply the induction principle. This principle involves moving an electric conductor relative to a magnetic field. In order to generate a significant electric current or voltage, however, the motion must be as rapid as possible and/or a powerful magnetic field is required. However, both of these requirements are difficult to meet in a wave power plant, especially if the translational motion of the waves is to be converted directly into electrical energy. The translational motion generated by ocean waves via the floating bodies is generally too slow for efficient utilisation of the induction effect, or else a device suitable for this purpose is too elaborate and/or expensive.
Nonetheless, ocean waves are capable of producing a relatively powerful translational force which can be used to generate electrical energy after conversion into rotational motion. Here, however, implementation is not possible using a crankshaft in the case of varying wave heights as is common in open waters (see explanations above). The use of racks and gears coupled with freewheel units to convert the translational motion into unidirectional rotational motion cannot be achieved in an optimum technological and economical manner and only with great complexity due to the weather conditions and the sensitive mechanical system of the freewheel units, as explained above.
Another wave stroke power plant, which is assumed in the preamble of the invention is shown in DE 10 2010 027 361 A1. Here a wave stroke power plant is shown with a floating body guided on a guide rod which is anchored on the seabed, the floating body being raised and lowered by the waves. By the force of gravity alone, the floating body slips back down into the wave trough after the wave crest has passed. The floating body is guided by guide rollers arranged in a guide cage, whereby the guide cage, together with the guide rollers, forms two bearing points in the longitudinal direction of the guide rod. On one side of the guide rod, a rack is also arranged which interlocks with a cogwheel that is additionally positioned in the guide basket of the floating body. The gear that interlocks with the rack drives an electrical generator via a transmission with integrated freewheel units, the electrical generator also being mounted on the floating body. The electric current generated is fed by a transformer to the mainland, for example. The device shown in DE 10 2010 027 361 A1 to generate electrical energy from the lifting motion of the ocean waves exhibits numerous components, in particular electrical components, which require special protection from penetration or corrosive attack by water, in particular sea water. For this reason, the known system is high-maintenance and does not offer optimum commercial viability. For permanent operation, the device according to DE 10 2010 027 361 A1 requires a high degree of maintenance and costly precautionary measures.
From DE 695 20 678 T2, a transport carriage is known which subdivides the load-bearing body into two partial bodies, each of which is connected to a wheel. The two partial bodies are pivotally interconnected by a joint, with the rotation axis of the joint running parallel to the wheel's rotation axes and running in the plane of the wheel's rotation axes. The two partial bodies are pivotally supported by a connecting spring arrangement around the rotation axis of the joint so that the wheels are elastically pressed against the guide rail, whereby the pressing forces are adjustable. In order to drive the transport carriage, electric motors are arranged on each partial body that drive the wheels, the wheels being able to roll on opposite sides of a guide rail.